class Demo
{
    String temp = "hello";
}

public class ZhaiZhiJie
{
    public static void main(String[] args)
    {
        Demo str1 = new Demo();
        str1.temp = "world";
        System.out.println("fun()方法调用前：" + str1.temp);
        fun(str1);
        System.out.println("fun()方法调用后：" + str1.temp);
    }
    public static void fun(Demo str2)
    {
        str2.temp = "MLDN";
    }
}